Offshore horizontal product lay arrangement

ABSTRACT

An arrangement that brings all of the separate elements of equipment used to lay product offshore such as pipe, umbilicals and power cables and assembles them into a single device that can be installed on a vessel of opportunity is described. A base is used for mounting, integration, and installation of the separate elements onto a vessel. The base receives a movable lay chute, an apparatus for moving and stabilizing the lay chute, a movable hang off clamp and work table, a movable access platform, a product support arm and wheel, and a fixed chute.

RELATED APPLICATION INFORMATION

This application is a Continuation In Part Application of applicationSer. No. 13/548,316 filed on Jul. 13, 2012.

FIELD AND BACKGROUND OF INVENTION

The invention is generally related to laying of product offshore andmore particularly to an arrangement for laying products such as pipe,umbilical lines (umbilicals), and power cables.

A-frames, cranes, and chutes have been used in the past to overboard endterminations of flexible pipes, umbilicals, and power cables (referredto hereinafter as products). In the prior art, these structures have allbeen separate pieces of equipment and not known to be fully integratedtogether as a single unit.

The separate pieces of equipment and their function are brieflydiscussed below.

In the most general terms, a vessel is used to transport products to anoffshore location where they are to be installed. A tension machine orreel drive arrangement will support the tension generated from the selfweight of the product spanning from the installation vessel down to theseabed or between the installation vessel and another fixed or floatingplatform where the product is being installed to or from.

A chute is used to control the bend radius of the product during layingoperations, and is the means of redirecting the product from a generallyhorizontal plane, over the side (any side including stern), and into thewater in a generally vertical plane.

While overboarding the second end, or making connections between twoproducts, a crane or A-frame is used to lift the end termination overthe chute while maintaining tangency of the product to the chute.

A hang-off clamp work table is used to support the weight of a producthanging in catenary, while the initiating end of a subsequent product isaligned over the top of the clamped product and the two connectedtogether in a vertical orientation below the chute. The chute isgenerally fixed at an elevation sufficient to make the connection abovethe hang-off clamp work table.

A problem with having many different parts that must work together isthat the level of complexity for vessel mobilization is increased wheninstalling and configuring all of the different parts in order to worktogether properly. The amount of time required for installation andconfiguration is also increased.

Thus, it can be seen that there is a need for an improved product layingarrangement that reduces the complexity and time required forinstallation and configuration.

SUMMARY OF INVENTION

The present invention addresses the shortcomings in the known art and isdrawn to an arrangement that brings all of the separate elementsdiscussed above and assembles them into a single device that can beinstalled on a vessel of opportunity, and includes functionalimprovements of each to optimize the use of the arrangement as a unit. Abase is used for mounting, integration, and installation of the separateelements onto a vessel. The base receives a movable lay chute, means formoving and stabilizing the lay chute, a movable hang of clamp and worktable, a movable access platform, a product support arm and wheel, and afixed chute.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming partof this disclosure. For a better understanding of the present invention,and the operating advantages attained by its use, reference is made tothe accompanying drawings and descriptive matter, forming a part of thisdisclosure, in which a preferred embodiment of the invention isillustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, forming a part of this specification, andin which reference numerals shown in the drawings designate like orcorresponding parts throughout the same:

FIG. 1 is an elevation of a vessel with the product lay arrangementinstalled.

FIG. 2 is a top view of a vessel with the product lay arrangementinstalled.

FIG. 3 is a perspective view of the product lay arrangement.

FIG. 4 is a detail view of the product lay arrangement showing the hangoff clamp and work table in the open position.

FIG. 5 is a detail view of the product lay arrangement showing the hangoff clamp and work table in the closed position.

FIGS. 6 and 7 illustrate the A-frame and roller being raised andlowered.

FIG. 8 is a section view of a portion of the movable chute.

FIG. 9 is the section view of the portion of the chute indicated in FIG.8.

FIG. 10 illustrates the range of product movement through the fixedchute.

FIG. 11 is an elevation view that illustrates movement of the A-frameand roller during operation.

FIGS. 12-16 schematically illustrate operations during handling andinstallation of bend restrictors.

FIGS. 17 and 18 illustrate the support of the movable work platform.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As seen in FIGS. 1 and 2 the offshore product lay arrangement 10(referred to as “product lay arrangement” hereinafter) is installed on avessel 12. As seen in FIG. 3, the product lay arrangement 10 includes abase 14, a movable A-frame 16 with a product support wheel 18, a movablelay chute 20, a movable hang off clamp and work table 22, a fixed chute24, and a movable work platform 26.

As seen in FIG. 3, the base 14 and equipment thereon are designed to beself contained for ease of installation onto a vessel, as seen in FIGS.1 and 2, as well as removal when the product lay arrangement 10 is nolonger required on a particular vessel or needed on a different vessel.The base 14 and equipment thereon are formed from a suitable materialsuch as steel. The base 14 is the structural support that distributesthe weight and operation loads of the invention onto the working deck ofthe vessel 12 and is designed for a balanced and fully assembled lift ofthe invention onto or off of a vessel. The base 14 controls the spacingof all components and aligns them for safe and optimal performance.

As seen in FIGS. 3, 6, 7, and 11-16, the A-frame 16 has two arms, witheach arm pivotally mounted on the base 14. At each arm of the A-frame 16is a hydraulic ram 28 that has one end pivotally mounted on the base 14and the opposite end pivotally mounted on the arm of the A-frame 16.This allows selective movement of the A-frame 16 during product layingoperations to obtain the optimum angle and height of product supportwheel 18 for supporting and laying product. Product support wheel 18 isrotatably mounted between the arms of the A-frame at the traveling endof the A-frame 16, which is the end away from the base. The A-frame 16may also have adjustable length arms to better accommodate a larger sizevariety of products and accessories attached to the products. Asdescribed below and seen in FIGS. 11 and 12, the product wheel 18 alsoserves as a wire rope sheave for moving items such as an end fitting 60and a bend restrictor assembly 62 into position. As seen in FIGS. 3 and17, the radial center of the lay chute 20 is at the pivotal connection35 which shares a common rotation axis with the pivotal connection 37 ofthe A-frame 16 when the lay chute 20 is in its lower position. As bestseen in FIG. 13, brace 36 A is pivotally connected, indicated by numeral35, to long side 31 of triangular frame 30. It is seen in FIGS. 12-18that pivotal connection 35 represents the radial center of the lay chute20. As seen in FIG. 13, the pivotal connection 37 of the A-frame 16serves as the axis of rotation for the A-frame. It is seen in FIG. 17that, while the lay chute 20 is in its lower (overboarding) position,the axis of rotation through the pivotal connection 37 of the A-frame 16is common with the axis of rotation of the pivotal connection 35 (radialcenter of lay chute 20).

Movable lay chute 20 receives and guides product being laid. Whilemovable lay chute 20 preferably has a fixed radius of curvature, it isseen in FIGS. 3 and 11-18 that it is mounted for selective movement onthe base 14 to change the relative position of the lay chute 20 toobtain the optimum angle and height for laying product. As best seen inFIG. 12-18, movable lay chute 20 is mounted on a triangular frame 30.The movable lay chute 20 is flared progressively and tangentiallyaligned with the curvature of the fixed chute 24. The geometry of thelay chute 20 allows the product to be radius controlled with the laychute 20 in any position.

The long side 31 (best seen in FIG. 12-16) of the triangular frame 30 ispivotally mounted (indicated by numeral 32) on the base 14. For ease ofillustration and aid in understanding the invention, the pivotconnection 32 is illustrated separately from the base 14 in FIG. 12-16.A hydraulic ram 34 has one end connected to the base 14 and the oppositeend connected to a brace 36 on the triangular frame 30. A sliding chutesupport 38 (seen in FIGS. 3 and 18) has its lower end rigidly attachedto the base 14 while its upper end slidably receives the lay chute 20.The support 38 stabilizes the lay chute 20 in the horizontal direction.A curved rail on the support 38 is preferably centered at the rotationpoint of the lay chute 20 to provide support at any achievable positionof the lay chute 20. The combination of the pivot connection 32, thehydraulic ram 34, and chute support 38 allow selective, stable movementof the lay chute 20 during product laying operations as required forsupporting the product and movement of equipment such as pipe line endterminations or branches attached to the product.

As seen in FIG. 8, the sides of the lay chute 20 are provided with waterspray nozzles 40 that serve to cool the product as it slides on thesurface of the chute 20. While only one nozzle 40 is shown in the crosssection of FIG. 8 on each side of the lay chute 20 for ease ofillustration, it should be understood that a series of water nozzles 40are preferably provided along the length of the lay chute 20.

As seen in FIG. 8, the surface of the lay chute 20 in contact with theproduct is preferably curved (concave) for better retention and guidanceof the product. As seen in FIGS. 8 and 9, the surface of the lay chute20 in contact with the product is also preferably lined with a frictionreducing material 46 such as polymeric sheeting.

The movable hang off clamp/work table 22, best seen in FIGS. 3-5 and10-18, is split into two halves that include the clamp 54 and worksurface 56. The fixed chute 24 is also attached to the lower portion ofeach half of the clamp/work table 22. The clamp 54 is used to hold endfittings or other accessories in place during the makeup of mid-lineconnections (flanged connections between two segments of product). Theclamp 54 is shown open in FIG. 4 and closed in FIG. 5. The clamp 54slides open and closed symmetrically about the centerline of the device.

The fixed chute 24 is curved outward from top to bottom and designed toprotect the product from contact with the hang off clamp supportingstructure, thus allowing the invention to lay product in the horizontaldirection as seen in FIGS. 10 and 11. FIGS. 10 and 11 illustrate, bothvertical and horizontal laying of product.

The movable work platform 26, best seen in FIGS. 17 and 18, pivots abouta fixed point 42 on the lay chute 20 and is kept horizontal by means ofa linkage 43 that completes an effective mechanical parallelogram. Theeffective mechanical parallelogram, indicated by dashed line 48, iscreated by the stairs 47, a linkage, and pivot point 42. The linkage 43is comprised of two arms 44 and 45. A first, short arm 44 extends downto and is pinned at the bottom of the stair support strut 50. A second,long arm 45 is pivotally attached at one end to the first, short arm 44below pivot point 42 and pivotally attached at its second end to theframe 14 as indicated by numeral 52. The COG (Center Of Gravity) of thework platform 26 will cause the linkage 43 to work in compression tokeep the platform 26 level. For example, a person standing on theplatform 26 may cause the COG to shift to the right, and cause thelinkage 43 to work in tension.

In operation, the product 58, which may be an item such as a pipe orumbilical line, is directed from a loaded position on the vessel 12 overthe support wheel 18, onto the lay chute 20, and then down through themovable hang off clamp/work table 22. During movement of the product,the water spray nozzles 40 on the lay chute 20 are used to reducefriction and protect the product and the lay chute. As seen in FIGS. 6,7, and 11-16 the positions of the A-frame 16 and movable lay chute 20are adjusted as required to obtain the optimum angle for movement of theproduct. This can be especially important when the product is pipe whichmust be maintained within certain specifications relative to its bendradius. The different positions are also used for movement ofaccessories such as pipeline end terminations, bend restrictor elements,and umbilical termination assemblies. FIG. 11 illustrates the use andmovement of the A-frame 16 and movable lay chute 20 to move the end ofan umbilical line and its end fitting 60 into position above the movablehang off clamp/work table 22 such that the end fitting 60 does notcontact and damage the movable lay chute 20. FIG. 12 illustrates themovement of a bend restrictor assembly 62 to the hang off clamp/worktable 22. FIGS. 13-15 illustrate the use of the hang off clamp/worktable 22 to support the product 58 and bend restrictor assembly 62 inplace for attaching additional product 58 and then lowering thecombination. FIG. 16 illustrates the use of the hang off clamp/worktable to retain a bend restrictor assembly 62 in place for theattachment of an end termination 64.

The invention provides the following advantages.

The invention can be lifted as a single unit and powered by a singlehydraulic power unit (HPU).

This significantly reduces the mobilization time onto vessels ofopportunity by reducing the scope and complexity of the physical work,as well as simplifying the engineering of the interfaces.

The integrated support base guarantees the device will function properlyand safely no matter where it is installed.

The positions and sizes of all the components are optimized to enablemaximum work space below the movable lay chute when needed, and reducesthe required length of the A-frame, further reducing the loads in theA-frame since the movable lay chute can be lowered to an optimalposition for its use.

The option for an adjustable length A-frame within the strength capacityof the integrated support base increases the quantity of potential work.

The compact design enables the invention to be installed on a largernumber of available vessels.

The integrated A-frame provides a means of over boarding up to themaximum load of the device and enables product installation from vesselsthat would have otherwise been passed over due to insufficient cranecapacity.

While specific embodiments and/or details of the invention have beenshown and described above to illustrate the application of theprinciples of the invention, it is understood that this invention may beembodied as more fully described in the claims, or as otherwise known bythose skilled in the art (including any and all equivalents), withoutdeparting from such principles.

What is claimed as invention is:
 1. A modular, portable product layarrangement for an offshore vessel, comprising: a. a base; b. a laychute movably mounted on the base; c. an A-frame pivotally mounted onthe base such that the A-frame has a pivoting end and a traveling end,with the A-frame having an axis of rotation that is common with theradial center of the lay chute when the lay chute is in a lowerposition; d. a combined hang off clamp and work table mounted at one endof the base; and e. a fixed chute attached to the hang off clamp andwork table.
 2. The arrangement of claim 1, wherein: a, the movable laychute is mounted on a frame; b. the frame has one end pivotally mountedon the base; and c. means for selectively moving the frame and the laychute is attached to the base and the frame.
 3. The arrangement of claim1, further comprising a combined product support wheel and wire ropesheave rotatably mounted on the traveling end of the A-frame.
 4. Thearrangement of claim 1, further comprising a movable work platformpositioned above the base and adjacent the lay chute.
 5. The arrangementof claim 1, wherein the combined hang off clamp and work table ismovably attached to the base for selectively opening and closing forallowing movement of the product or supporting the product.
 6. Amodular, portable product lay arrangement for an offshore vessel,comprising: a. a base; b. a lay chute supported by a frame movablymounted on the base; c. an A-frame pivotally mounted on the base suchthat the A-frame has a pivoting end and a traveling end, with theA-frame having an axis of rotation that is common with the radial centerof the lay chute when the lay chute is in a lower position; d. acombined product support wheel and wire rope sheave rotatably mounted onthe traveling end of the A-frame; e. a combined hang off clamp and worktable mounted at one end of the base; and; f. a fixed chute attached tothe hang off clamp and work table.
 7. The arrangement of claim 6,wherein: a. the frame supporting the lay chute has one end pivotallymounted on the base; and b. means for selectively moving the frame andthe lay chute is attached to the base and the frame.
 8. The arrangementof claim 6, further comprising a movable work platform positioned abovethe base and adjacent the lay chute.
 9. The arrangement of claim 6,wherein the combined hang off clamp and work table is movably attachedto the base for selectively opening and closing for allowing movement ofthe product or supporting the product.
 10. A modular, portable productlay arrangement for an offshore vessel, comprising: a. a base; b. a laychute supported by a frame movably mounted on the base; c. an A-framepivotally mounted on the base such that the A-frame has a pivoting endand a traveling end, with the A-frame having an axis of rotation that iscommon with the radial center of the lay chute when the lay chute is ina lower position; d. a combined product support wheel and wire ropesheave rotatably mounted on the traveling end of the A-frame; e. theframe supporting the lay chute having one end pivotally mounted on thebase; f. means for selectively moving the frame and the lay chute; g. amovable work platform positioned above the base and adjacent the laychute; h. a combined hang off clamp and work table mounted at one end ofthe base; and i. a fixed chute attached to the combined hang off clampand work table.
 11. The arrangement of claim 10, wherein the combinedhang off clamp and work table is movably attached to the base forselectively opening and closing for allowing movement of the product orsupporting the product.